Progression seems to slow to a halt after tier 1, Skill points begin to accumulate too slow and the upgrades are too expensive, they also don't add major changes for the high price of the upgrade. 125 skill points for -3 boss hp is a waste of skill points. I'm only halfway tier 2 and have played the game for around 1 day. The 1st tier took around an hour so the time upscale is quite concerning as I have 5 tiers to go.
The Samurai helper is useless past stage 3, as at LV:6 he only does 7 damage per second. it would take him around 3 minutes to defeat the stage by himself, but I could kill the tier 4 enemy much faster without him.
