Currently there are only two things i dislike in game.
1. After first boss, player gets in shop, and there are never 99 coins gathered at this moment, so why irritate player with listing useful thing 99 price, if garanteed player wouldn't be able to buy it?! Plus, as i noticed, things that were not bought will not appear in next shops, so it's sure "item lost for this run".. Especially it irritates when later you have more money than can spend, but those "not-bought" things are lost.
2. Pills mechanics. Each run they change effect - fine. but why there is no way to see description before picking one, when i already checked what it does and know the effect? Eventually it comes to figuring out the colours of 1 pill i feel useful for this run, and skipping all others = not fun.
Yet, i don't understand abilities of some:
-Faster speed doesn't seem to do anything(though in theory should be cool faster shooting buff);
-Slower speed as i understand is a de-buff, so just irritates by mere existence;
-Something wrong feels like mutator, changing baby behaviour - interesting idea, but as it's difficult to figure out if it won't make good baby into crappy one, i just skip all these.
BTW, am i right that heart producing baby is not influenced by pills? Feels like this, neither Faster speed nor Power pill make one produce more hearts.(shame)