JusTiCe8
Nice beginning 🙂
It seems you used EVERY second you had (0.6s later would have been too late) to pick up all 3 coins in level 12 and complete it (it seems you lost a life in a previous level but gained an extra one with the 20th coin collected). Hopefully you will get further soon !
If you want to replay a level, you can save your game at the end of the previous level (SAVE GAME choice in your screenshot, you may use different slots if you want to save several ones) and reload it from the CAMPAIGN menu (LOAD GAME choice).
About secret codes, only one word to say : explore, explore, explore ! If you manage to find the secrets #1 and #3, for example, it means that the code of secret #2 is somewhere to be found between the levels where you found the codes of the 2 other secrets.
To switch on a monitor, just touch it (maybe I should add this in the HELP menu), it often takes a bit of dexterity to reach it.
One last thing : if you use the F12 key in a downloaded version of the game (by the way, what's your OS ?), you will directly save a PNG screenshot in its root directory (I used it a lot during tests and to grow my game gallery). At the end of any game (when you lose your last life), an automatic screenshot is saved (also in the game root directory).
Hope that helps !