Gems, keys and the alternate ending
Apply the original checkpoint rule and plan the colored-gem returns.
Original 1996 PlayStation release; English NTSC-U/PAL rules. Japanese changes and N. Sane Trilogy are outside this guide.
The original gem condition
For every gem in the English original, break all counted crates and finish without dying after activating the first checkpoint. A death before that checkpoint can start a fresh attempt; a later death means restarting the level for the gem. Deaths inside bonus rounds do not spoil this condition, and bonus-round crates do not count toward the main level's gem. This applies to clear gems as well as colored gems. The 2017 remake changes the collection rules, so a modern guide that allows ordinary clear-gem deaths is unsuitable for this version.
Collect colors before sweeping the map
The English original's colored-gem locations are The Lost City for green, Generator Room for orange, Toxic Waste for blue, Slippery Climb for red, The Lab for yellow and Lights Out for purple. Each still requires the qualifying crate run. Lights Out needs the yellow-gem route, so collect yellow before attempting purple. Keep a written list of these six rewards, then return to earlier stages containing their platforms. Japanese releases change some gem locations; these instructions use the English game. Practise the hard return route before committing to a full clean run.
Unlock the two key stages and finish
Three Cortex tokens in Sunset Vista and Jaws of Darkness lead to bonus rounds that award keys when completed. The keys open Whole Hog and Fumbling in the Dark, which also belong in a complete collection. There are 20 clear gems and six colored gems in the English original. The clear-gem route in The Great Hall leads toward the alternate ending with Tawna. Check the map for missing rewards rather than assuming the final boss alone means full completion. Record each newly earned gem or key when the game offers a save opportunity.
A post-checkpoint death invalidates an original-game gem attempt even if you break every crate after respawning.
Picture details
Game artwork belongs to its respective rights holders.