The game has a high skill ceiling and there is a fuck ton to learn but none of that is necessary. The game gets progressively hard as most do and there are some difficult levels (impact was one iirc) but it is by no means industry standard breaking, dark soul type game of tower defence. And the second planet erekir was surprisingly easy but I was already familiar with the game at that point so might be harder for new players but still fairly easy to play through (compared to serpulo).

Don't be averted by the disclaimer if you don't like difficult games. You might fail a couple times but one you learn how or why you failed, you can easily be prepared the next time. Give it a shot and there is a good chance you might like it. Don't get on public multiplayer servers without finishing the campaign tho, you might not have a good time till you learn everything. If you really wanna try multiplayer servers, try not to disturb others and listen to what the veterans suggest.