Thanks for your advice, I really want to improve those small things that can make a huge difference. Sadly that texture bug still happens sometimes, I have a function that takes lots of small textures and stitches them together, but sometimes it introduces those strange borders. I will try to fix it soon.
More people also asked for a on-screen pad to control the characters, I'll add one.

And yes, you found one of my inspirations, Lost Vikings!
I did not know about Eggerland though, but from what I've seen, it also seems to have similar concepts