I just finished it too. Here's my massive post of feedback and thoughts:
I sorta-kinda wish I waited a little longer to play it. This game has signs that it was a labor of love all over it, but unfortunately bugs just seemed to creep in. I enjoy catching and squashing bugs, but I did feel it detracted from the experience. If I waited a week or two, I could have probably played a more refined game. But...I can replay it again some time in the future.
World, story, and characters:
Lovely, all very lovely. The characters are great and charming. I enjoyed the humor, the sorrow, the reveals - all of it.
The world is genuinely interesting and deserves to be explored. I kind of like how we aren't shown a map of the world, but we are told about its places. It's kind of fun to picture what could be out there. I really hope I will be able to see more of the world in the future. There's something special here.
I've written a lot below. A lot of it is ideas for if we were to see a sequel or expansion...but I just want to make it clear that these ideas are just...ideas. They wouldn't necessarily make the game better. Seith ultimately knows what's best and I hope he continues work as a game developer. None of this is to put down his work.
I like the puzzles already in the game and I feel there should be more of them. There could also be more physical puzzles too. Probably not something contrived like pushing blocks in a dungeon, but there could have seen more done with the current mechanics in the game. Maybe puzzles where you strategically place brisine and light the correct fuse to strategically demolish something, or puzzles where you have to physically change the environment in the correct order to successfully move to the other end of a room. Puzzles that relied on your knowledge of the lore were interesting. I wouldn't mind seeing more of that too.
I entered the game thinking stealth would have a much larger role, but it really doesn't. Once you complete the guard outfit or figure out you can just run past the guards - stealth is no longer important, and I don't think the game needs to focus on stealth.
One part I enjoyed was leaping over the rock columns in the catacombs. I wouldn't mind seeing more platforming elements like that. Nothing cartoonish like other 3D platformers, but what if Tilo could scurry up ropes and swing on them? What if he could climb ledges like in Uncharted? What if he could swim underwater to find lost artifacts? I'm not saying the game should be more like Zelda or something, and I know that adding features definitely doesn't improve a game (despite what many arm-chair developers would think), but I do feel that there could be more focus on the aspects of being a mouse.
These could be much more intense. I'm not going to talk about the rat guards, but lets focus on the other enemies.
Before I entered the catacombs, I thought these would be a much larger threat. The first spider you meet is immediately killed by a trap it must walk into. The second spider won't seem to follow you even when you throw bottles at it. If you have enough bottles to throw, then you're practically safe as it will die very quickly.
What if thrown items only stunned and didn't kill here? I think it would be interesting if Tilo had to use the environment to his advantage. Let's picture this: The catacomb has a lot more spiders, and maybe they respawn too. To defeat spiders, Tilo would have to get their attention and lead them into traps he set across the catacombs. Maybe Tilo could position and set spider traps, or he could start fires with the grease jars and lead spiders into them. While this is all happening, Tilo would have to leap over chasms and traps while the spiders lept and followed.
Unfortunately, once you know that the hole with purple smoke is deadly, these guys are no longer an enemy. You just stay away from the holes until you have pinecones. I think it would be more interesting if these guys were completely hidden underground - and when they were about to strike, the ground could rumble and Tilo would have to get away before they emerged. Maybe some areas of the catacombs could could have 'soft' ground where any area of the floor could have a worm appear. That could tie into a puzzle too - Tilo would have to lay down stone blocks on the soft ground so he can carry something to the other end of a room safely. Unfortunately right now, these guys are just like doors. They block the path until you find a key (pinecones).
I wanted to see these guys chase me to the ends of the earth and follow me to into the cave with the shortcut-basket while I narrowly escaped their first appearance...but that didn't happen. Although I couldn't sprint, they still couldn't seem to keep up with me too well. I'd like to see Tilo's arsenal come in use here. Like maybe being spotted is a game-over state with these guys (as you can't hide), so you have to do something creative like attracting them to a bottle of brisine with a stick, then throwing a stick at the stuff to blow them up. Overall I think their presence could have been a little more drawn out too.
I really hope this game does well. Not only do I want to see more of the world and the story, but I also want to see the gaming world at large support the work of Seith. I remember reading a while ago that he realized that if he didn't make this game, then no one would ever, ever see the world and ideas he had. I'm really glad he decided to go for it. Game development is scary. It's got one of the harshest audiences, it has a massive learning curve, it doesn't always pay well - there's a lot of things to overcome. I'm glad Seith went through with it, and I look forward to seeing his future endeavors.