Thanks for the feedback and detailed review. I can't say I gave that much thought to the side-on/topdown viewing angles, but I suppose it is a bit unusual now you mention it xD I'm very new to drawing my own sprites
I should definitely have mentioned on the menu that slimes hitting you causes life loss, I got stuck for time and put a hint of that kind in the description but yeah it wasn't clear. With more time, a small knockback and colour effect would be something I'd definitely go for.
The spawn rate of the slimes was fixed and increased slightly each wave - however *where* the slimes were spawning was random and I wonder if what happened there was that I gave too wide a range for them to spawn in and so if too many spawn far away by chance one round, it appears as if the spawn rate is lower. I probably just need to keep track of roughly where they're spawning and make sure not too many get bunched up or too far out.