Debugging: Inside the Machine is a free debugging-practice arcade
platformer for students preparing
for AP Computer Science Principles
or AP Computer Science A. You're inside a corrupted machine — find the
USB Key, fix the glitches, and escape the firewall before the system
collapses.
CSP and CSA modes ship in the same app. Tap once to switch.
— EASY · MED · HARD —
Each difficulty is a different level, with its own glitch tilemap and
its own question bank. CSP topics: Selection, Iteration, Functions &
Lists. CSA topics: Variables · Strings, Iteration · Loops, Arrays ·
Recursion. Two bonus levels (K-Pop Demon Hunters, Minecraft) unlock
when you've cleared all three difficulties.
— CODE LENS —
Glitches scatter across each level as collectible bugs. When you're in
range, the CODE LENS button pulses on screen. Tap it and a real
multiple-choice debugging question appears: read the broken code, pick
the actual bug from four explanations, and the glitch repairs.
Wrong answer? Stability drops 10 percent. Right answer? Stability
recovers 5 percent and the level inches closer to stable.
— Real questions, not filler —
Every question is hand-written and scoped to AP exam topics. No
random AI hallucinations, no off-curriculum trivia. The pseudocode
reference card (CSP) and Java Quick Reference (CSA) are one tap away
during any question.
— Built for phones and tablets —
Touch controls only. Bottom-left D-pad to move, big JUMP button on the
right, hold for higher jump. Question screens use full-size answer
buttons. Designed for landscape iPhone and iPad.
— Offline, no account, no tracking —
Everything ships in the app. The game makes zero network calls,
collects zero analytics, and requires no sign-in.
— More from CS++ —
A "More from CS++" button connects you to the rest of the CS++ family:
the AP CSP and AP CSA full-curriculum apps, the CS++ Java IDE for
on-device Java practice, and the free csplusplus.com web resources
(curriculum, vocab trainer, practice exams).
For: AP CSP and AP CSA students, CS teachers building exam prep
sessions, anyone who likes finding bugs.
Screenshots of Debugging: Inside the Machine iOS app
