Difficult one-button arcade. See Full Review for roadmap and helpful advice. Has a fairly long (but fully idle-able) death grind. ~25+ hours to 100%, heavily based on skill.
Difficult one-button arcade. See Full Review for roadmap and helpful advice. Has a fairly long (but fully idle-able) death grind. ~25+ hours to 100%, heavily based on skill.
You unlock nightmare levels by collecting all three gears in a level (orbs, score, secrets), which can be done over multiple runs.
Start by getting all the orbs for each level, which can often be combined with getting the secrets for the level on the same run. The path you take for the orbs are not only a guaranteed safe path, but they help with routing the nightmare levels. It's also good practice for seeing where there is leeway for less clicks for the scoring runs you will most likely have to do separately.
Regarding the 'Perfect Run' achievement, you can re-earn the gears for orbs and score, but not for secrets. Once you collect a secret and finish the level having collected it, you cannot collect it again (but you can still use the secret path). Save the first level's secret for later to make it easy, though you may get a scoring gear unintentionally while going for orbs/secrets runs.
For the skins you get by getting high scores in Endless (15k, 50k, and 60k), make sure to die after getting to 15k and 50k score, as you can't unlock multiple skins for the same run unfortunately.
I strongly recommend watching this video for routing the nightmare levels. It will save you quite a lot of trial and error from obstacles that appear faster than you can react.
Even if you struggle quite a lot you will almost certainly have a fair amount of death grind left over. Try to find a checkpoint that starts with you having a faster speed (or where you just die faster), to minimize the time between deaths. I personally used a late checkpoint in the Worms level, which netted me 1000 deaths every 54 minutes.
