Like Menace said above. 0.33 ohms, 5W, and not 33 ohms...
Easy to test on a DMM in continuity/beep test, such good resistor should read almost like a short.
And opened (infinite resistance) if burned/opened.
To prove that the resistor is indeed bad/opened, and if you have two alligator clips, you can try
connecting two alligator clips in series, and connecting the other ends to R1, e.g.
to left side of R1 <----- alligator clip #1 -----><------ alligator clip #2----> to right side of R1
Make sure the clips ends do not touch any other electrical connections with the playfield up or down
(use electrical tape if you must), and see if the flash lamps now work.
The two alligator clips in-series would add a few tenths of a ohms across them, thus temporarily somewhat replacing the resistor (if opened).
Do not do this alligator clips trick with any resistor value greater than 0.50 ohms, as the clips are close to a dead short...
Cheers,
- Sylvain.