This was the level that was the biggest roadblock in the game for a very, very long time. Base After Base sure does a poor job at preparing the player for what I consider to be one of the biggest difficulty jumps the main levels have to offer. I like it quite a bit though. It'll throw off a new player quite well, and absolutely forces the player to adjust to being upside down, which is something I love, and although the final three of the original seven levels don't exactly introduce new gameplay mechanics, they test and teach the player the more complex concepts of gameplay that can be found in the game. (Although, I wouldn't say Base After Base is very complex). The flipped gravity part near the end of the level works perfectly for this (along with potentially forcing the players into using practice mode, another aspect of the game that wasn't necessarily needed prior to reaching this, but would be an absolutely massive help to any new player attempting to beat it). I still prefer Jumper as the finale for 1.0, but I do think this is a far bigger curveball for newer players. Shame I've noticed this being discussed in a negative light quite a bit, because this is probably one of my favorites of the original 7.