I love slimes :D
I enjoyed this, but I have a slight problem with the slime spawning and cap- currently as it stands, since there is such a high potential cap on slimes after upgrades the optimal strategy is to just sit and wait for a minute before attacking once, causing a massive chain reaction that kills all slimes having used only one hit's worth of stamina, which makes runs way too long and slow due to the waiting. I'd suggest lowering the cap upgrades and increasing the spawnrate upgrades, so you can still get use out of the death rattle upgrades, but with less waiting and shorter runs.
but yeah I love slimes :D