It is a Nintendo 64 thing that looks like it might adapt N64 carts to a cabinet?

Photos: N64

IDENTITY: Stats Box for NFL Blitz. This cart reader would allow you to move your team and player statistics from the NFL Blitz arcade game to the Nintendo 64 version at home.

This Whatsit is an Opto Encoder of some kind. I see no manufacturer marking on the board. There is a 6 pin jumper, a 2 pin jumper and an opto sensor on the back. There are two holes near the middle that look like they were designed to allow for some alignment.

I recognized two NPN TIP122 transistors, a momentary switch, a 74C14 Inverter and a 2N2222a.

M-4 REV 3.1 are etched on the parts side. 9530 and DXL-1 94V0 are etched on the solder / opto sensor side.

IDENTITY: Deltronic ticket counter, part of a ticket dispenser.

The 2764 has a label on it

For purposes of identifying chips:
A1 is a 20 pin DIP unmarked
B1 is a 14 pin DIP 74LS74
C1 is a 20 pin DIP unmarked
B2 is a 40 pin DIP unmarked
D3 is a 28 pin socketed DIP 2764 EPROM
A4 is a 20 pin DIP marked N32S153N, barely legible, may be wrong
B4 is a 14 pin DIP 7404

Our first whatsit is linked to Donkey Kong or Donkey Kong Jr. because it was in a pile of Jr. parts. It appears to plug into a 40 pin DIP and act as a daughterboard. High Score save kit?